A typical access control system includes card readers and proximity readers, usually located near an access point such as a door that provides controlled access to or exit from a limited access area. Signals from the card readers and proximity readers are forwarded to a control panel which in turn controls door locks.
Typically, panels, card readers and proximity detectors require 12 volts. Some door locks require 12 volts for operation while others may require 24 volts. Systems may include both 12-volt and 24-volt locks. To be able to support all devices, multiple power supplies are needed to provide the various voltages. Each power supply will likely have excessive ratings because it is unknown how much current/power is going to be needed from each voltage source. Where the system is battery-backed, a different battery is needed for each voltage to be supplied.
Further, the power supplies (12-volt and 24-volt) are unmanaged, potentially resulting in unplanned loss of power and unpredictable performance. This makes scheduled maintenance extremely difficult, and may result in unnecessary and unscheduled maintenance.